/* mdb_stat.c - memory-mapped database status tool */
/*
 * Copyright 2011-2021 Howard Chu, Symas Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted only as authorized by the OpenLDAP
 * Public License.
 *
 * A copy of this license is available in the file LICENSE in the
 * top-level directory of the distribution or, alternatively, at
 * <http://www.OpenLDAP.org/license.html>.
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "lmdb.h"

#define Z	MDB_FMT_Z
#define Yu	MDB_PRIy(u)

static void prstat(MDB_stat *ms)
{
#if 0
	printf("  Page size: %u\n", ms->ms_psize);
#endif
    printf("  Tree depth: %u\n", ms->ms_depth);
    printf("  Branch pages: %"Yu"\n",   ms->ms_branch_pages);
    printf("  Leaf pages: %"Yu"\n",     ms->ms_leaf_pages);
    printf("  Overflow pages: %"Yu"\n", ms->ms_overflow_pages);
    printf("  Entries: %"Yu"\n",        ms->ms_entries);
}

static void usage(char *prog)
{
    fprintf(stderr, "usage: %s [-V] [-n] [-e] [-r[r]] [-f[f[f]]] [-v] [-a|-s subdb] dbpath\n", prog);
    exit(EXIT_FAILURE);
}

int main(int argc, char *argv[])
{
    int i, rc;
    MDB_env *env;
    MDB_txn *txn;
    MDB_dbi dbi;
    MDB_stat mst;
    MDB_envinfo mei;
    char *prog = argv[0];
    char *envname;
    char *subname = NULL;
    int alldbs = 0, envinfo = 0, envflags = 0, freinfo = 0, rdrinfo = 0;

    if (argc < 2) {
        usage(prog);
    }

    /* -a: print stat of main DB and all subDBs
	 * -s: print stat of only the named subDB
	 * -e: print env info
	 * -f: print freelist info
	 * -r: print reader info
	 * -n: use NOSUBDIR flag on env_open
	 * -v: use previous snapshot
	 * -V: print version and exit
	 * (default) print stat of only the main DB
     */
    while ((i = getopt(argc, argv, "Vaefnrs:v")) != EOF) {
        switch(i) {
        case 'V':
            printf("%s\n", MDB_VERSION_STRING);
            exit(0);
            break;
        case 'a':
            if (subname)
                usage(prog);
            alldbs++;
            break;
        case 'e':
            envinfo++;
            break;
        case 'f':
            freinfo++;
            break;
        case 'n':
            envflags |= MDB_NOSUBDIR;
            break;
        //case 'v':
        //    envflags |= MDB_PREVSNAPSHOT;
        //    break;
        case 'r':
            rdrinfo++;
            break;
        case 's':
            if (alldbs)
                usage(prog);
            subname = optarg;
            break;
        default:
            usage(prog);
        }
    }

    if (optind != argc - 1)
        usage(prog);

    envname = argv[optind];
    rc = mdb_env_create(&env);
    if (rc) {
        fprintf(stderr, "mdb_env_create failed, error %d %s\n", rc, mdb_strerror(rc));
        return EXIT_FAILURE;
    }

    if (alldbs || subname) {
        mdb_env_set_maxdbs(env, 4);
    }

    rc = mdb_env_open(env, envname, envflags | MDB_RDONLY, 0664);
    if (rc) {
        fprintf(stderr, "mdb_env_open failed, error %d %s\n", rc, mdb_strerror(rc));
        goto env_close;
    }

    if (envinfo) {
        (void)mdb_env_stat(env, &mst);
        (void)mdb_env_info(env, &mei);
        printf("Environment Info\n");
        printf("  Map address: %p\n", mei.me_mapaddr);
        printf("  Map size: %"Yu"\n", mei.me_mapsize);
        printf("  Page size: %u\n", mst.ms_psize);
        printf("  Max pages: %"Yu"\n", mei.me_mapsize / mst.ms_psize);
        printf("  Number of pages used: %"Yu"\n", mei.me_last_pgno+1);
        printf("  Last transaction ID: %"Yu"\n", mei.me_last_txnid);
        printf("  Max readers: %u\n", mei.me_maxreaders);
        printf("  Number of readers used: %u\n", mei.me_numreaders);
    }

    if (rdrinfo) {
        printf("Reader Table Status\n");
        rc = mdb_reader_list(env, (MDB_msg_func *)fputs, stdout);
        if (rdrinfo > 1) {
            int dead;
            mdb_reader_check(env, &dead);
            printf("  %d stale readers cleared.\n", dead);
            rc = mdb_reader_list(env, (MDB_msg_func *)fputs, stdout);
        }
        if (!(subname || alldbs || freinfo))
            goto env_close;
    }

    rc = mdb_txn_begin(env, NULL, MDB_RDONLY, &txn);
    if (rc) {
        fprintf(stderr, "mdb_txn_begin failed, error %d %s\n", rc, mdb_strerror(rc));
        goto env_close;
    }

    if (freinfo) {
        MDB_cursor *cursor;
        MDB_val key, data;
        mdb_size_t pages = 0, *iptr;

        printf("Freelist Status\n");
        dbi = 0;
        rc = mdb_cursor_open(txn, dbi, &cursor);
        if (rc) {
            fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
            goto txn_abort;
        }
        rc = mdb_stat(txn, dbi, &mst);
        if (rc) {
            fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
            goto txn_abort;
        }
        prstat(&mst);
        while ((rc = mdb_cursor_get(cursor, &key, &data, MDB_NEXT)) == 0) {
            iptr = data.mv_data;
            pages += *iptr;
            if (freinfo > 1) {
                char *bad = "";
                mdb_size_t pg, prev;
                ssize_t i, j, span = 0;
                j = *iptr++;
                for (i = j, prev = 1; --i >= 0; ) {
                    pg = iptr[i];
                    if (pg <= prev)
                        bad = " [bad sequence]";
                    prev = pg;
                    pg += span;
                    for (; i >= span && iptr[i-span] == pg; span++, pg++) ;
                }
                printf("    Transaction %"Yu", %"Z"d pages, maxspan %"Z"d%s\n",
                       *(mdb_size_t *)key.mv_data, j, span, bad);
                if (freinfo > 2) {
                    for (--j; j >= 0; ) {
                        pg = iptr[j];
                        for (span=1; --j >= 0 && iptr[j] == pg+span; span++) ;
                        printf(span>1 ? "     %9"Yu"[%"Z"d]\n" : "     %9"Yu"\n",
                               pg, span);
                    }
                }
            }
        }
        mdb_cursor_close(cursor);
        printf("  Free pages: %"Yu"\n", pages);
    }

    rc = mdb_open(txn, subname, 0, &dbi);
    if (rc) {
        fprintf(stderr, "mdb_open failed, error %d %s\n", rc, mdb_strerror(rc));
        goto txn_abort;
    }

    rc = mdb_stat(txn, dbi, &mst);
    if (rc) {
        fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
        goto txn_abort;
    }
    printf("Status of %s\n", subname ? subname : "Main DB");
    prstat(&mst);

    if (alldbs) {
        MDB_cursor *cursor;
        MDB_val key;

        rc = mdb_cursor_open(txn, dbi, &cursor);
        if (rc) {
            fprintf(stderr, "mdb_cursor_open failed, error %d %s\n", rc, mdb_strerror(rc));
            goto txn_abort;
        }
        while ((rc = mdb_cursor_get(cursor, &key, NULL, MDB_NEXT_NODUP)) == 0) {
            char *str;
            MDB_dbi db2;
            if (memchr(key.mv_data, '\0', key.mv_size))
                continue;
            str = malloc(key.mv_size+1);
            memcpy(str, key.mv_data, key.mv_size);
            str[key.mv_size] = '\0';
            rc = mdb_open(txn, str, 0, &db2);
            if (rc == MDB_SUCCESS)
                printf("Status of %s\n", str);
            free(str);
            if (rc) continue;
            rc = mdb_stat(txn, db2, &mst);
            if (rc) {
                fprintf(stderr, "mdb_stat failed, error %d %s\n", rc, mdb_strerror(rc));
                goto txn_abort;
            }
            prstat(&mst);
            mdb_close(env, db2);
        }
        mdb_cursor_close(cursor);
    }

    if (rc == MDB_NOTFOUND)
        rc = MDB_SUCCESS;

    mdb_close(env, dbi);
txn_abort:
    mdb_txn_abort(txn);
env_close:
    mdb_env_close(env);

    return rc ? EXIT_FAILURE : EXIT_SUCCESS;
}